Ultrasound-guided simultaneous lateral pterygoid muscle and bilaminar zone injection to treat temporal mandibular joint anterior disc displacement with reduction

BACKGROUND: Anterior disc displacement with reduction (ADDwR) most frequently occurs in temporomandibular joint disorder (TMD) and poses a major clinical challenge. Both botulinum toxin (BTX) and hypertonic dextrose (HD) injections have been reported for the treatment of ADDwR. However, the clinical confirmation of precise injection into the lateral pterygoid muscle and bilaminar zone is difficult. This study evaluated ultrasound-guided injection of BTX and HD for the treatment of ADDwR. METHODS: Thirty patients with ADDwR received real-time ultrasound-guided injection of 30 units of BTX and 0.2 ml of 50% HD. Primary outcomes included Visual Analogue Scale (VAS) scores for joint pain and clicking, and maximum opening. The secondary outcome was the Fricton score, and data were collected before treatment, and at 1 month and 6 months post-treatment. RESULTS: At 1 month, VAS scores for joint pain and clicking decreased significantly, maximum opening increased markedly, and Fricton scores also showed a significant reduction (P < 0.01). At the 6-month follow-up, improvements in maximum opening and joint clicking remained statistically significant, although the degree of improvement was reduced compared with the 1-month assessment (P < 0.05). In contrast, improvement in joint pain was no longer statistically significant (P = 0.369). The Palpation Index, Craniomandibular Index and Dysfunction Index still showed significant improvement (P < 0.05). CONCLUSION: Ultrasound-guided precision combined injection of BTX and HD represents a viable short-term therapeutic option for anterior disc displacement with reduction.